In public parks, large gardens, sports facilities such as stadiums and the like, and golf courses large lawns need constant care due to aesthetic appearance or the application of the lawn. First of all the lawn must be mowed regularly especially during summer to keep the lawn short.
Several different types of lawn mowers may be used to cut the grass. The simplest kind of lawn mower is the manual reel mower, which is pushed by a person.
Powered mowers utilise some kind of engine to rotate the cutting blades. Engines may be of the electrical or internal combustion type. A powered push mower is the simplest type of powered mower—the engine rotates the cutters, while a person pushes the mower forward.
Internal combustion engines applied to lawn mowing are almost invariably of the four-strokes or two strokes variety using gasoline (e.g. petrol) as fuel. Internal combustion engines used with lawn mowers are usually provided with only one cylinder. The power ranges from 2 to 6 horsepower (1.5 to 4.5 kW). The engines are usually carburetted and require a manual pull to start them, although an electric start may also be applied.
During the last fifty or so years electrically powered mowers have existed, however, the disadvantage of these lawn mowers are that they require a trailing power cord, which limits their range, thus they are only suitable for relatively small lawns as a power socket is essential.
A pull mower is essentially the same as a manually pushed mower, however, the propulsion unit pulls the mowing unit instead of pushing it. It is the same principal behind a tractor or an animal drawn mower.
An alternative mechanism for cutting grass is a horizontally spinning blade held close above the grass surface. This type is usually referred to as a rotary mower. One of the first companies to exploit this principle commercially was the Australian Victa company, in 1947. Usually, these mowers are moved by manual motive power—the on-board engine or motor only spins the blades. The most common type is fitted with wheels, rotary mowers typically have an opening in the side of the housing, where the cut grass is expelled. Some have a grass catcher attachment at that point to bag the grass clippings. Rear-catchers are another common design for the same purpose.
Hover mowers are powered rotary push mowers that use a turbine above the spinning blades to drive air downwards, thereby creating an air cushion that lifts the mower off the ground. The operator can then easily move the mower as it floats over the grass.
Hover mowers are necessarily light to achieve the air cushion and typically have plastic bodies with an electric motor, although small petrol engines have been used. A different style of movement is often employed with hover mowers whereby operators swing the mower in an arc around themselves because there are no wheels touching the ground to impede movement in sideway directions.
Hover mowers can also be applied to very long grass and even light scrub, since with their lightness, most operators are able to lift the mower up and then let it sink slowly down while the blades progressively chop up the vegetation (when lifted, of course the air cushion disappears). The lifting action is made even easier when the mower is swung around with the handle held against the operator's mid-body to provide leverage.
Professional grass-cutting equipment (used by large establishments such as universities or local authorities, etc) usually takes the form of much larger dedicated ride-on platforms or attachments that can be mounted on a standard tractor unit or behind (“gang-mower”). Either type may use rotating blades or the cylindrical blade type cutters.
There are two main types of cutting mechanisms:                those where a set of spiral-cylindrical blades spins on a horizontal axis (reel mower). The cutting is done in a scissor like manner between the moving spiral blades and a single stationary horizontal blade. The axle is attached to a gear, which is mounted on one of the wheels to spin the blades rapidly to obtain a good grass cutting action even when the mower moves slowly.        those where a number of blades spin horizontally on a vertical drive shaft (rotary mower). The mechanism cuts the grass as horizontal blades strike the grass at high speed.        
On rotary mowers the blade is seldom sharp enough to cut the grass blades. The speed of the blade simply tears the grass resulting in brown tips. By contrast, the cylinder-type lawnmowers and manual lawnmowers usually work by scissor action on the blades and a cleaner cut is achieved. Hence it is advantageous to use the reel mower when the appearance of the lawn is essential, e.g. golf courses, parks or the like.
In case large lawns need to be mowed it is impossible to use an ordinary domestic lawn mower, as this takes up too much time and is physically strenuous for the person operating the lawn mower.
To ease the burden of lawn moving the lawnmower may be self-propelled using its own engine. Thus the person doing the lawn moving only needs to steer the lawn mower in the right direction. However, it still takes up too much time to mow a large lawn.
To save time it is obvious to apply lawnmowers, which are pushed or pulled by a vehicle e.g. a tractor, a mini-tractor or an ATV. Typically, a number of wide lawnmower modules are attached to a vehicle in an overlapping pattern or the lawnmower has a substantial width, hence it is possible to cut wide lanes of the lawn during one passing of the vehicle.
The drawbacks of the above reel lawnmowers are that:                The width of the lawnmower or lawnmower modules makes it necessary to maintain a small distance between the moving spiral blades and the single stationary horizontal blade, hence reducing the cutting efficiency. If the moving spiral blades and the single stationary horizontal blade are maintained very close, heat generation occurs in the single stationary horizontal blade when the lawnmower or lawnmower modules are driven rapidly ahead. If overheated the single stationary horizontal blade folds and thereby damages the moving spiral blades and prevents them from cutting any grass.        The width of the lawnmower or lawnmower modules can prevent even cutting of an uneven lawn, because the moving spiral blades and the single stationary horizontal blade are fixed between the wheels of the lawnmower or lawnmower modules.        